This invention relates generally to radio frequency antenna and more particularly to radio frequency antenna adapted to operate over relatively wide frequency bandwidths.
As is known in the art, many installations for array antennas impose physical constraints on the size of such antennas. For example, in an airborne installation each one of the antenna elements in the array thereof should have minimum depth, width and thickness. Further, in many applications it is necessary that the antenna operate over a relatively wide bandwidth and handle relatively high amounts of power during transmission of radio frequency energy. One antenna element which has the appropriate size for airborne installations and which is capable of handling high amounts of power is a double-ridged rectangular waveguide fed by a coaxial transmission line; however, such antenna element is limited in its operating bandwidth.